roll back the firmware

tell me, now flooded with firmware from benF 3.64. but at the moment you need native firmware (which goes to the purchase date). preferably in HEX format (APP and LIB).

These have been sold with various versions of the firmware installed, so the question is where did you buy it and exactly when?

recently bought the eBay, about a month ago, then updated to BenF 3.64 and now can `t flash inhomogeneous version below, or another author.If you have the original firmware that came with the sale, in HEX format, please lay.
learned was APP Ver3.01, if there is in hex ​​format?